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Lectures and Colloquia during the semester



July 4, 2005

Freie Universität Berlin - Institut für Informatik
Takustraße 9
14195 Berlin
Room 005           - map -
Lecture - 14:15

Johanes Blömer - Universität Paderborn

Cryptography on smartcards - side-channel attacks and countermeasures

Abstract: If cryptographic primitives like an RSA signature run on a smartcard, security issues that are not considered in classical cryptography arise. In particular, even an adversary that gets hold of a smartcard and can observe and manipulate the smartcard should not be able to deduce the secret information that is stored on the card. Observing the card includes taking time or power consumption measurements. Manipulating a card includes the induction of faults into computations of the card. Attacks using measurements and fault induction are called side-channel attacks. In the talk I will survey current techniques for side-channel attacks. I will also discuss countermeasures that protect against certain side-channel attacks.


Colloquium - 16:00

Éric Fusy -INRIA Rocquencourt

Transversal structures on triangulations, with application to graph drawing

Abstract: We focus on a particular family of triangulations, said irreducible, which essentially correspond to 4-connected triangulations. These triangulations can be endowed with a structure that we call transversal edge-partition. As it is the case for the set of Schnyder Woods of a triangulation, the set of transversal edge-partitions of an irreducible triangulation is a distributive lattice. In addition, the minimal transversal edge-partition can be used to associate a ternary tree to the triangulation in a bijective way.

A new straight-line drawing algorithm for irreducible triangulations, based on face-counting principles, can be derived from the transversal structure. Thanks to the bijection between ternary trees and irreducible triangulations, the size of the grid can be analyzed and is proven to be smaller by a factor 27/22 than the grid dimensions of the previously known algorithms.


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